Hydraulic control system



Feb. 18, 1941. L T. ARGO 2,232,357

HYDRAULIC CONTROL SYSTEM Filed Nov. 21, 1958 2 Sheets-Sheet 1 2Sheets-Sheet 2 ZllS/'e Argo L. T. ARGO Filed Nov. 21, 1938 HYDRAULICCONTROL SYSTEM Feb. 18, 1941.

Patented Feb. 18, 1941 HYDRAULIC CONTROL SYSTEM Lisle T. Argo, LosAngeles, Calif.; assignor to Kay- Brunner Steel Products, Inc., acommi/.ion of Delaware Application November 21, 1938, Serial No. 241,651

2 Claims.

The present invention relates to improvements in hydraulic controlapparatus which embodies a new hydraulic system for effecting andcontrolling the operation of various machines and devices such, forexample, as the earth moving implements of road building, excavating andsimilar machines.

It has been the practice to control the operation of such implementswith a plurality of hydraulic rams, pumpsiand valves in an arrangementwherein a pump and a valve means are required for each ram and thus eachram unit constitutes a complete hydraulic system independent of theother rams.

as in being bulky and space consuming and com-` paratively expensive,and also diflicult of operation, as to its multiple units.

It is therefore an important object of this invention to provide ahydraulic control system such as described, wherein a single pump orother source of pressure fluid; together with valves of specialconstruction and arrangement, and a single circulatory system for thepressure iluid, are inter-connected with one another `and a plurality ofhydraulic rams so as to constitute a complete system or unit affordingthe same selective operation and control as the systems having aplurality of pumps, but consisting of fewer parts and being morecompact, less expensive and easier of installation and operation thansuch multiple pump systems. v

Another object of this invention is to provide a control system of thecharacter described by means of which a positive and quickly responsiveoperation of th'e rams is insured, due to the particular manner hereprovided of applying the.

uid pressure thereto from a single pu'mp through selectively operablevalves and a single closed system of pipes and conduits, and duefurther, to the fact that the pump continuously circulates the pressurefluid at operating pressure, between it and said valves while. thecontrol system hereof is subject to operation. A

A further object is to provide a system of the character describedwherein the valves are so constructed and arranged as -to make possiblea continuous circulation of the operating fluid between them and thepump at operating pressure and without being influenced as to movementby said fluid, the fluid pressure on the valves being equalized in allpositions of the latter.

Yet another object of this invention is .to provide a control devicewhich primarily embodies a valve assembly and valve operating means as aof standard piping, with a. plurality of standardA rams and a singlepump, whereby to provide an improved hydraulic system in accordance withthis invention.

In the accompanying drawings, which illustrate one embodiment of myinvention,

Figure 1 is a fragmentary vertical sectional view of one form of valveassembly and valve operating means which makes possible the systemhereof, being taken on the plane of line l-I of Fig. 2.

Fig. 2 is a sectional view taken on the plane of line 2-2 of Fig. 1.

Fig. 3 is a sectional view taken on the plane of line 3-3 of Fig. l.

' Fig. 4 is a sectional view taken on the plane of lines I--I of Figs. 1and 2.

Fig. 5 is a perspective view of the valve assembly shown in Fig. 1.

Fig. 6 is a schematic view of the complete system hereof showing twohydraulic rams subject to independent and simultaneous operation, uponappropriate valve manipulation.

Figs. '1, 8, 9, 10 and 11 are schematic sections of the valvesshown inthe various positions assumed during the operation of the system shownin Fig. 6.

Referring more specifically to the embodiment of the' invention shown inthe accompanying drawings, it is seen with reference to Figs. 1 1to 5,inclusive, that an especially constructed valve device or assembly Amakes possible the novel system hereof, as illustrated in Fig. 6, whenconnected with a plurality of standard hydraulic rams B and C and asingle pump D of suitable design and having a supply connection Ewith asource'F of fluid, such as oil.

As shown in Fig. 6,

pressure and suction linesG and H respectively Before specificallydescribing the valve assembly it should be noted that the 4hydraulicsystem hereof, provides for continuous operation of the pump D wherebythe tiuid is circulated through the valve-assembly at operating pressureduring the time the system is in readiness for operation. For example,if the system hereof is installed on road building orearth workingvehicles or apparatus for the purpose of determining and varying theposition of the blade or other earth moving implement thereof, the pumpmay be connectedwith the motor unit of the vehicle or apparatus .so as`to bel operated simultaneously therewith. It is thought unnecessary tofurtner illustrate this or any other typical applications of the system,inasmuch as it is suicient to point out that the pump D may be operatedcontinuously in any suitable manner, lto prepare the systern foroperation. With this provision the fluid operating pressure is morequickly and effectively applied to the rams upon appropriatemanipulation of the valves embodied in the valve assembly A, andtherefore a better control of the rams is made possible.

A's particularly shown in Figs. l to 5, inclusive, the valve assembly Acomprises a housing I2 of sectional construction and suitablypartitioned to define therein, a pressure chamber I3 and a suctionchamber I4. The pressure chamber has ya uid intake opening |5 with whichis connected the line G from the pump D, Whereas the suction chamber hasan outlet opening I6 with which is connected the suction line H of saidpump. As here shown the housing I2 is provided with valve chambers I1and I8 extending side by side and separated by a common wall orpartition I9. Hollow cylindrical or -other suitable constructed valves20 and 2| are reciprocally mounted in the chambers I1 and I8 and providefor control of the rams B and C respectively.

Valve operating rods 22 and 23 are slidable through suitable oil seals24 and openings 26 in the wall 21 of the housing I2 and extend throughthe valves`20 and 2| so that the inner ends thereof may be threadedlysecured to the apertured members 28 at certain corresponding ends of thevalves. The outer ends of these rods are provided with yokes 29 engagedin the usual manner with valve operating levers 30 and 3|, which latterprovide for selective operation of the valves.

The valve chambers I1 and I8 and the valves are identical as toconstruction, except for the arrangement of ports and passages therein,and may best be described in the following description of the operationof the system.

Assuming that both valves are in neutral position, as shown in Fig. 6,and the system is ready for operation with the pump circulating theoperating fluid through the valve assembly, it is seen that the fluidpasses from the pump-through the line G and opening I5 to pressurechamber I3 and after entering said chamber, will pass through a singleport 32 (see Figs. 4 and 6) in the valve chamber II into an annulargroove 33 formed exteriorly of the valve 20, but as this groove is notin communication with any port or outlet at this time, the fluid will beineiective at this point. Also, at this time, fluid will pass from thepressure chamber I3 through ports 34 and 35 in the valve chamber I8.Fluid passing through port 34 enters an annular groove 35 in theexterior of valve 2| but this groove is now closed. However, the uidpassing through port 35 entersa groove 31 in the valve 2|, correspondingto groove 36 but which is in registration with a passage 38 extendingthrough the partition I9 into the valve chamber II, whereby to conductthe fluid to the latter. Fluid thus entering the chamber I1 enters anannular groove 39 inlthe valve 20 and thence ows through openings 40 insaid groove, into the bore of said valve and then ilows through saidbore into an extension 4| of the suction chamber I4 and thence throughopening I6 and return or suction line H back to the pump D.

It is now seen that the fluid circulates con- -tinuously through thevalve assembly but does not tend to move the valves, due to theconstruction and arrangement of the latter. In this connection it shouldbe noted that to insure equal fluid pressures on the valves 20 and 2|,the end members 28 thereof are provided with pilot rods 42 slidable insuitably packed openings 43 in the wall 44 of the valve assembly housingI2, these extensions being of the same diameter as the valve operatingrods 22 and 23 which extend through the other ends of the valves andserving in effect, as extensions of said operating rods.

Should it be desiredto retract or move inwardly the plunger or piston Nof the ram B, as shown in Fig. 6, the operator manipulates the operatinglever 30 t-o move the valve 20 into the position shown in Fig. 9 whilethe valve 2| remains in neutral position. The operating fluid now flowsfrom pump D through line G, opening I5, pressure chamber I3, port 32,groove 33, port 45 and pipe line K to the outer end of the ram B. Theplunger N now moves inwardly and fluid between it and the inner end ofthe ram is expelled from the ram back to the pump D (see Fig. 9) throughpipe line J, port 46 of the valve chamber I1, groove 39 and itsassociated openings 40 in valve 20, bore of said valve extension 4| ofsuction chamber I4 and thence through chamber I4 outlet opening I6 andline H to the pump. Thus it is seen that the operating iluid circulatescontinuously during the operation of the ram as Well as when the ram isat rest.

To extend the plunger N of ram B outwardly, as seen in Fig. 6, theoperator manipulates the lever 30 to position the valve, as shown inFig. 10, and the course of the operating fluid is from pressure chamberI3, port 32, valve groove 33, port 46, pipe line J to the inner end ofthe ram, whereby to extend said plunger. The fluid between said plungerand the outer end of the ram is returned to the pump through the line K,port 45, groove 49, openings 50 leading from said groove to the bore ofthe valve 20, and from said bore to the suction chamber I4 and thencethrough the return line H.

, To operate the ram C whereby to retract the plunger O shown in Fig. 6,the operator manipulates the lever 3| whereby to position the valve 2|,as shown in Fig. 7, and the operating fluid ows from the pressurechamberA I3 through the then open port 35, groove31, port 5| of valvechamber I8, pipe line M to the outer end of the ram. As the plunger Omoves inwardly the fluid between it and the inner end of the ram returnsto the pump through the line L, port 52 of valve chamber I8, groove 53in valve 2|, openings 54, the bore of the valve, and thence through anextension 4| of the suction chamber I4, the suction chamber proper,opening I6, and line H to the pump D.

To extend the plunger O of ram C, the valve 2| is moved to the positionshown in Fig. 8, and the operating fluidfnow flows from the pressurechamber I3, through port 34, groove 36 of valve 2|, port 52, pipe line Lto the inner end of the ram C. As the plunger O moves outwardly, thefluid between it and the outer end of the ram returns to the pump Dthrough the line M, port 5I, groove 53, openings 54, bore of the valve2|, and then through the return chambers 4| and I4, opening I6 and lineH to the pump.

As shown in Fig. 11, the valves 20 and 2| are positioned to bring out asimultaneous inward or retractive movement of the plungers N and O ofthe two rams and in this case the flow of uid is the same as describedin connection with Figs. 7 and 9. By positioning both valves as perFigs. 8 and 10, the plunger of the rams will be simultaneously extendedin the same manner as hereinbefore described in connection with Figs. v8and aasass'r 10. It is obvious that the valve may also be set to retractthe plunger of one oi the rams while the plunger oi.' the other is,extended.

A pressure relief valve P is embodied in the valve assembly for. thepurpose o! automatically i relieving to the suction chamber il excessive58 closing said port on the suction chamber side r of the latter, asshown in Figs. 1 and 6. The valve 58 is cup-shaped and from its closedor seat end a tubular stem 59 projects through the port 56 into thepressure chamber. On the outer end of this stem is a piston 60 slidablein a dash-pot cylinder BI. The tubular stem communicates the cylinderwith the interior of the cup-like valve 58. whereby a supply of theoperating uid from the suction chamber il may pass through a port 62 ina chamber 53 in which the skirt of the valve 58 is slidable, and enterthe cylinder 8i through said tubular stem. A slotted valve member il isat all times seated against the end of the tubular` stem which extendsthrough the valve 58 and so held by a. spring Bihaving suitable tensionadjusting-means 66. The slot in the valve permits of a restricted ow ofiluid through the stem.

. The spring 65 and the valve member 6| serve to hold the pressurerelief valve 58 seated,` the tension of said spring determining thepressure at which said relief valve will function. This dash-pot deviceoperatesto prevent chattering of the relief valve 58. The pressureexposed area of the piston 60 is smaller than that of the valve 58 sothat at pressures beyond safe limits the piston 60 will not interferewith or retard due opening of the relief valve. Should the relief valveopen the fluid in the pressure chamber il will pass through the'port 58into the suction chamber il. As the piston B0 moves outward duringopening of valve 58 the fluid will be drawn from the chamber il, port62, chamber I3. valve 58, and tubular stem 59 into the cylinder li.

It will now be apparent that the valve means h and associatedstructures, as described. in this specication and .illustrated in theaccompanying drawings, make possible a hydraulic system whichconstitutes an improvement in the art, for the following reasons:

1. The use of a single pump for operatingland controlling a pluralityvof hydraulic rams or like devices: l l

C2. The simplicity of arrangement and the reduction of the number ofparts and elements as.,

compared to the usual requirements in multiple ram operating devices andsystems corresponding to the one of the present inventions:

3. The provision of simple, compact and readily installable lvalve means-wherein the valves are constructed and arranged so that, the pressure lthereon is equalized V in all positionsthereof and the valves. will notvtend to move under the fluid pressure valve in any position.'

, tgfcontinuously circulating the operating-huida operatingzpressurefrom a v assembly lwhile the operation to provide a system is inreadiness quicker response oithe vhydraulically operated` devicesupon'manipulation ofthe valve,

Iclaimtj- 1.A =Ajv alve assembly; for a hydraulic system,

including-.ia housing having a pressure chamber andv a suction 'ch-amberadapted respectively for connection with the outlet and the inlet of lacirculating pump, a first valve chamber. a second valve chamber,extensions providing communicating between the suction chamber and oneend of both valve chambers, openings leading to and from each of saidvalve chambers adapted for circulating iluid pressure to and fromhydraulically responsive devices, a single pressure port leading fromthe pressure chamber to the first valve chamber, a pair of pressureportsvleading from the pressure chamber to the second valve chamber, apassage leading from one of said pair oi' ports to the ilrst valvechamber; a ilrst valve sli'dable in the first valve chamber, said valvebeing hollow and having two end peripheral grooves and -an intermediateperipheral groove; ports leading into said valve from saidv end grooves;a second valve slida'ble. in the lsecond valve chamber, said secondvalve being hollowand having two end peripheral grooves and anintermediate peripheral groove; ports leading into the second valve fromsaid intermediate groove: means for actuating the first `valve toselectively place either end groove into registration with one oi' theopenings of the ilrst valve chamber while maintaining .the intermediategroove in communication with said single pressure port and the otheropening respectively, and to place one of said end grooves inregistration with one end of said passage; and means for actuating thesecond valve to selectively place either end groove into registrationwith one of the openings and one of the pressure ports of the secondvalve chamber respectively, while the intermediate groove is placed inregistration with the other opening, and to place one of said endgrooves in registration with the other end of said passage, whereby whensaid end groove of the ilrst valve is in registration with said passage,iluid is free to circulate through said pump and housing.

2. A valve assembly for a hydraulic system, including a housing having apressure chamber and a suction chamber adapted'respectively forconnection with .the outlet and the inlet of a circulating pump, saidhousing also having a first valve chamber adapted for connection to ahydraulically responsive device, a second valve chamber adapted forconnection to asecond hydraulically responsive. device,V both of saidvalve chambers at one and the same end being at all times incommunication with the suction chamber, a single port for placing thepressure cham- Yber in communication with the first valve chamber, apair of ports for placing the pressure chamber in communication with thesecond valve chamber, a providing communication between'the .two valvechambers at the other ends thereof; a pair oi' valves in said chamberseach tubular and axially movable in the respective chamber from aneutral position to either of two extreme positions for controlling theapplication of iiuid yto said devices through said ports, means on onevalve for placing the second valve chamber in communication with one endof said passage through one oi' said pair of ports when said T. ARGO.

